1. Field
This invention relates to the art of tire repair, and more particularly to an improved method and tire repair plug for repairing and sealing punctures in vehicle tires.
2. State of the Art
Various means for repairing tire punctures are disclosed in the prior art, all of which may be considered to be types of plugs which are sealably inserted into the puncture hole.
Some plugging devices are designed to be inserted into the puncture hole from the interior side (i.e. normally pressurized side) of the tire. Exemplary of such plugs are those found in U.S. Pat. No. 3,308,867 of Nitzsche, U.S. Pat. No. 2,902,074 of Langdon, U.S. Pat. No. 3,842,887 of Mendes and U.S. Pat. Nos. 4,579,161 and 4,802,388 of Roberts. The use of such plugs is disadvantageous because it requires removal of the tire from the rim. Thus, roadside repairs are generally impractical. For the typical motorist, the repair must be performed in a commercial automotive tire repair shop at extra time and expense.
Other plugs are designed to be driven or pulled into a puncture with a removable rod or "needle." Such devices are described in U.S. Pat. No. 2,966,189 of Chambers et al., U.S. Pat. No. 3,174,524 of Nitzsche and U.S. Pat. No. 3,175,599 of Clifford.
The patent literature describes tire plugs which may be inserted into a puncture hole from the outside of the tire. Many have screw threads or circumferential ribs on the device which assist in retaining the plug within the puncture hole.
U.S. Pat. No. 570,942 of Merritt discloses a tapered screw having an enlarged head for receiving a machine screw. The underside of the screw head is concave for sealing against the tire surface. The tapered screw has fine V-threads of small pitch.
U.S. Pat. No. 2,727,554 of Westfall discloses a hollow, ribbed, cylindrical plug which is forced into a puncture hole by a rod. After insertion, a sealing "washer" within the hollowed plug remains rigid while the remaining plug portion collapses under the tire compression.
U.S. Pat. No. 4,279,343 of Alfanto describes an insertable resilient tire plug having a hollow body for containing a liquid rubber compound. The body has axial fins and a threaded head. During insertion, the plug body is twisted to wring out the liquid from the plug chambers.
U.S. Pat. No. 3,296,048 of Wolfe discloses a screw type plug for a tire puncture. The plug has standard symmetrical V-threads and the head is cut off by a hacksaw after installation.
U.S. Pat. No. 4,096,901 of Reichenbach discloses a rigid threaded tire plug including a tapered portion with standard symmetrical V-threads, and a fracturable finger-gripping handle.
U.S. Pat. No. 4,827,998 describes a threaded plug having a cylindrical non-tapered resilient shroud encasing a rigid screw.
All of the aforementioned tire plugs have disadvantages. Some of the plugs comprise multiple parts, resulting in added manufacturing expense. Others require removal of the tire from the vehicle wheel for repair. Specialized tools are required to install some plugs. Additionally, the ability of many plugs to maintain a permanent seal is highly dependent upon the installer's technique. A single component tire plug is needed which is readily formed, easy to install, has sufficient flexibility to absorb tire movement while maintaining a seal, and is resistant its ejection from the puncture hole.